The Chemistry of Powder and Explosives - Sciencemadness Dot Org

252 NITRIC ESTERS
It was then rinsed with a very dilute solution of potassium nitrate
(1 ounce to the gallon). The patent states that "the use of this
solution appears to add strength to the compound, but the use
of this solution and also potassium carbonate are not essential
and may be dispensed with." The product is pressed, opened out,
and dried at 150°F., and when dried it is fit for use. The patent
also covers the possibility of using instead of cotton "other matters
of vegetable origin and the possibility of carrying out the
nitration with nitric acid alone or with mixed acids of inferior
strength."
1846. Teschemacher 84 studied the preparation of guncotton
and demonstrated that no sulfuric acid is consumed by the reaction.
1847. Gladstone 86 by exercising special precautions was able
to carry out combustion analyses of xyloidine and of pyroxylin
prepared according to the directions, of Schonbein. Nitrogen was
determined by the differential method. The pyroxylin was found
to contain 12.75% nitrogen and was thought to correspond to a
pentanitrate while the xyloidine corresponded more nearly to a
trinitrate.
1847. Crum 8e nitrated cotton until he could introduce no
further nitrogen into the molecule, and analyzed the product for
nitric acid by the method which is used in the nitrometer. His
result calculated as nitrogen gives a figure of 13.69%. It is interesting
to note that Cram's cotton was "bleached by boiling in
caustic soda and put in a solution of bleaching powder; then
caustic soda again, and afterwards weak nitric acid. It was well
washed and beaten in a bag with water after each operation. , . .
The cotton, dried and carded after bleaching, was exposed in
parcels of 10 grains each for several hours to the heat of a steam
bath, and each parcel was immersed, while hot, into a 1 oz.
measure of the following mixture: Sulphuric acid (1.84) 1 measure,
and 3 measures of pale lemon-colored nitric acid (1.517).
After one hour it was washed in successive portions of water
until no trace of acid remained, and was then dried in the open
air"—or, for analysis, was dried completely in a vacuum desiccator
over sulfuric acid.
8* Mem. of the Chem. Soc, 253 (1846); MacDonald, op. cit., pp. 28-31.
a* Ibid., 412 (1847); MacDonald, op. cit., pp. 31^1.
86 Proc. Phil. Soc. Glasgow, 163 (1847); MacDonald, op. cit., pp. 21-27.